/***************************************************************************/
/*                                                                         */
/*  aflatin.c                                                              */
/*                                                                         */
/*    Auto-fitter hinting routines for latin script (body).                */
/*                                                                         */
/*  Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 by                  */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_ADVANCES_H

#include "aflatin.h"
#include "aferrors.h"


#ifdef AF_USE_WARPER
    #include "afwarp.h"
#endif


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****            L A T I N   G L O B A L   M E T R I C S            *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/

FT_LOCAL_DEF(void)
af_latin_metrics_init_widths(AF_LatinMetrics metrics,
                             FT_Face face,
                             FT_ULong charcode)
{
    /* scan the array of segments in each direction */
    AF_GlyphHintsRec hints[1];


    af_glyph_hints_init(hints, face->memory);

    metrics->axis[AF_DIMENSION_HORZ].width_count = 0;
    metrics->axis[AF_DIMENSION_VERT].width_count = 0;

    {
        FT_Error error;
        FT_UInt glyph_index;
        int dim;
        AF_LatinMetricsRec dummy[1];
        AF_Scaler scaler = &dummy->root.scaler;


        glyph_index = FT_Get_Char_Index(face, charcode);
        if (glyph_index == 0)
            goto Exit;

        error = FT_Load_Glyph(face, glyph_index, FT_LOAD_NO_SCALE);
        if (error || face->glyph->outline.n_points <= 0)
            goto Exit;

        FT_ZERO(dummy);

        dummy->units_per_em = metrics->units_per_em;
        scaler->x_scale = scaler->y_scale = 0x10000L;
        scaler->x_delta = scaler->y_delta = 0;
        scaler->face = face;
        scaler->render_mode = FT_RENDER_MODE_NORMAL;
        scaler->flags = 0;

        af_glyph_hints_rescale(hints, (AF_ScriptMetrics)dummy);

        error = af_glyph_hints_reload(hints, &face->glyph->outline, 0);
        if (error)
            goto Exit;

        for (dim = 0; dim < AF_DIMENSION_MAX; dim++)
        {
            AF_LatinAxis axis = &metrics->axis[dim];
            AF_AxisHints axhints = &hints->axis[dim];
            AF_Segment seg, limit, link;
            FT_UInt num_widths = 0;


            error = af_latin_hints_compute_segments(hints,
                                                    (AF_Dimension)dim);
            if (error)
                goto Exit;

            af_latin_hints_link_segments(hints,
                                         (AF_Dimension)dim);

            seg = axhints->segments;
            limit = seg + axhints->num_segments;

            for (; seg < limit; seg++)
            {
                link = seg->link;

                /* we only consider stem segments there! */
                if (link && link->link == seg && link > seg)
                {
                    FT_Pos dist;


                    dist = seg->pos - link->pos;
                    if (dist < 0)
                        dist = -dist;

                    if (num_widths < AF_LATIN_MAX_WIDTHS)
                        axis->widths[num_widths++].org = dist;
                }
            }

            af_sort_widths(num_widths, axis->widths);
            axis->width_count = num_widths;
        }

Exit:
        for (dim = 0; dim < AF_DIMENSION_MAX; dim++)
        {
            AF_LatinAxis axis = &metrics->axis[dim];
            FT_Pos stdw;


            stdw = (axis->width_count > 0)
                   ? axis->widths[0].org
                   : AF_LATIN_CONSTANT(metrics, 50);

            /* let's try 20% of the smallest width */
            axis->edge_distance_threshold = stdw / 5;
            axis->standard_width = stdw;
            axis->extra_light = 0;
        }
    }

    af_glyph_hints_done(hints);
}



#define AF_LATIN_MAX_TEST_CHARACTERS 12


static const char af_latin_blue_chars[AF_LATIN_MAX_BLUES]
[AF_LATIN_MAX_TEST_CHARACTERS + 1] =
{
    "THEZOCQS",
    "HEZLOCUS",
    "fijkdbh",
    "xzroesc",
    "xzroesc",
    "pqgjy"
};


static void
af_latin_metrics_init_blues(AF_LatinMetrics metrics,
                            FT_Face face)
{
    FT_Pos flats[AF_LATIN_MAX_TEST_CHARACTERS];
    FT_Pos rounds[AF_LATIN_MAX_TEST_CHARACTERS];
    FT_Int num_flats;
    FT_Int num_rounds;
    FT_Int bb;
    AF_LatinBlue blue;
    FT_Error error;
    AF_LatinAxis axis = &metrics->axis[AF_DIMENSION_VERT];
    FT_GlyphSlot glyph = face->glyph;


    /* we compute the blues simply by loading each character from the    */
    /* 'af_latin_blue_chars[blues]' string, then compute its top-most or */
    /* bottom-most points (depending on `AF_IS_TOP_BLUE')                */

    AF_LOG(("blue zones computation\n"));
    AF_LOG(("------------------------------------------------\n"));

    for (bb = 0; bb < AF_LATIN_BLUE_MAX; bb++)
    {
        const char* p = af_latin_blue_chars[bb];
        const char* limit = p + AF_LATIN_MAX_TEST_CHARACTERS;
        FT_Pos* blue_ref;
        FT_Pos* blue_shoot;


        AF_LOG(("blue %3d: ", bb));

        num_flats = 0;
        num_rounds = 0;

        for (; p < limit && *p; p++)
        {
            FT_UInt glyph_index;
            FT_Pos best_y;  /* same as points.y */
            FT_Int best_point, best_first, best_last;
            FT_Vector* points;
            FT_Bool round = 0;


            AF_LOG(("'%c'", *p));

            /* load the character in the face -- skip unknown or empty ones */
            glyph_index = FT_Get_Char_Index(face, (FT_UInt) * p);
            if (glyph_index == 0)
                continue;

            error = FT_Load_Glyph(face, glyph_index, FT_LOAD_NO_SCALE);
            if (error || glyph->outline.n_points <= 0)
                continue;

            /* now compute min or max point indices and coordinates */
            points = glyph->outline.points;
            best_point = -1;
            best_y = 0;   /* make compiler happy */
            best_first = 0; /* ditto */
            best_last = 0; /* ditto */

            {
                FT_Int nn;
                FT_Int first = 0;
                FT_Int last = -1;


                for (nn = 0; nn < glyph->outline.n_contours; first = last + 1, nn++)
                {
                    FT_Int old_best_point = best_point;
                    FT_Int pp;


                    last = glyph->outline.contours[nn];

                    /* Avoid single-point contours since they are never rasterized. */
                    /* In some fonts, they correspond to mark attachment points     */
                    /* which are way outside of the glyph's real outline.           */
                    if (last <= first)
                        continue;

                    if (AF_LATIN_IS_TOP_BLUE(bb))
                    {
                        for (pp = first; pp <= last; pp++)
                            if (best_point < 0 || points[pp].y > best_y)
                            {
                                best_point = pp;
                                best_y = points[pp].y;
                            }
                    }
                    else
                    {
                        for (pp = first; pp <= last; pp++)
                            if (best_point < 0 || points[pp].y < best_y)
                            {
                                best_point = pp;
                                best_y = points[pp].y;
                            }
                    }

                    if (best_point != old_best_point)
                    {
                        best_first = first;
                        best_last = last;
                    }
                }
                AF_LOG(("%5d", best_y));
            }

            /* now check whether the point belongs to a straight or round   */
            /* segment; we first need to find in which contour the extremum */
            /* lies, then inspect its previous and next points              */
            if (best_point >= 0)
            {
                FT_Int prev, next;
                FT_Pos dist;


                /* now look for the previous and next points that are not on the */
                /* same Y coordinate.  Threshold the `closeness'...              */
                prev = best_point;
                next = prev;

                do
                {
                    if (prev > best_first)
                        prev--;
                    else
                        prev = best_last;

                    dist = points[prev].y - best_y;
                    if (dist < -5 || dist > 5)
                        break;

                }
                while (prev != best_point);

                do
                {
                    if (next < best_last)
                        next++;
                    else
                        next = best_first;

                    dist = points[next].y - best_y;
                    if (dist < -5 || dist > 5)
                        break;

                }
                while (next != best_point);

                /* now, set the `round' flag depending on the segment's kind */
                round = FT_BOOL(
                    FT_CURVE_TAG(glyph->outline.tags[prev]) != FT_CURVE_TAG_ON ||
                    FT_CURVE_TAG(glyph->outline.tags[next]) != FT_CURVE_TAG_ON);

                AF_LOG(("%c ", round ? 'r' : 'f'));
            }

            if (round)
                rounds[num_rounds++] = best_y;
            else
                flats[num_flats++] = best_y;
        }

        AF_LOG(("\n"));

        if (num_flats == 0 && num_rounds == 0)
        {
            /*
             *  we couldn't find a single glyph to compute this blue zone,
             *  we will simply ignore it then
             */
            AF_LOG(("empty\n"));
            continue;
        }

        /* we have computed the contents of the `rounds' and `flats' tables, */
        /* now determine the reference and overshoot position of the blue -- */
        /* we simply take the median value after a simple sort               */
        af_sort_pos(num_rounds, rounds);
        af_sort_pos(num_flats, flats);

        blue = &axis->blues[axis->blue_count];
        blue_ref = &blue->ref.org;
        blue_shoot = &blue->shoot.org;

        axis->blue_count++;

        if (num_flats == 0)
        {
            *blue_ref =
                *blue_shoot = rounds[num_rounds / 2];
        }
        else if (num_rounds == 0)
        {
            *blue_ref =
                *blue_shoot = flats[num_flats / 2];
        }
        else
        {
            *blue_ref = flats[num_flats / 2];
            *blue_shoot = rounds[num_rounds / 2];
        }

        /* there are sometimes problems: if the overshoot position of top     */
        /* zones is under its reference position, or the opposite for bottom  */
        /* zones.  We must thus check everything there and correct the errors */
        if (*blue_shoot != *blue_ref)
        {
            FT_Pos ref = *blue_ref;
            FT_Pos shoot = *blue_shoot;
            FT_Bool over_ref = FT_BOOL(shoot > ref);


            if (AF_LATIN_IS_TOP_BLUE(bb) ^ over_ref)
                *blue_shoot = *blue_ref = (shoot + ref) / 2;
        }

        blue->flags = 0;
        if (AF_LATIN_IS_TOP_BLUE(bb))
            blue->flags |= AF_LATIN_BLUE_TOP;

        /*
         * The following flag is used later to adjust the y and x scales
         * in order to optimize the pixel grid alignment of the top of small
         * letters.
         */
        if (bb == AF_LATIN_BLUE_SMALL_TOP)
            blue->flags |= AF_LATIN_BLUE_ADJUSTMENT;

        AF_LOG(("-- ref = %ld, shoot = %ld\n", *blue_ref, *blue_shoot));
    }

    return;
}


FT_LOCAL_DEF(void)
af_latin_metrics_check_digits(AF_LatinMetrics metrics,
                              FT_Face face)
{
    FT_UInt i;
    FT_Bool started = 0, same_width = 1;
    FT_Fixed advance, old_advance = 0;


    /* check whether all ASCII digits have the same advance width; */
    /* digit `0' is 0x30 in all supported charmaps                 */
    for (i = 0x30; i <= 0x39; i++)
    {
        FT_UInt glyph_index;


        glyph_index = FT_Get_Char_Index(face, i);
        if (glyph_index == 0)
            continue;

        if (FT_Get_Advance(face, glyph_index,
                           FT_LOAD_NO_SCALE |
                           FT_LOAD_NO_HINTING |
                           FT_LOAD_IGNORE_TRANSFORM,
                           &advance))
            continue;

        if (started)
        {
            if (advance != old_advance)
            {
                same_width = 0;
                break;
            }
        }
        else
        {
            old_advance = advance;
            started = 1;
        }
    }

    metrics->root.digits_have_same_width = same_width;
}


FT_LOCAL_DEF(FT_Error)
af_latin_metrics_init(AF_LatinMetrics metrics,
                      FT_Face face)
{
    FT_Error error = AF_Err_Ok;
    FT_CharMap oldmap = face->charmap;
    FT_UInt ee;

    static const FT_Encoding latin_encodings[] =
    {
        FT_ENCODING_UNICODE,
        FT_ENCODING_APPLE_ROMAN,
        FT_ENCODING_ADOBE_STANDARD,
        FT_ENCODING_ADOBE_LATIN_1,
        FT_ENCODING_NONE /* end of list */
    };


    metrics->units_per_em = face->units_per_EM;

    /* do we have a latin charmap in there? */
    for (ee = 0; latin_encodings[ee] != FT_ENCODING_NONE; ee++)
    {
        error = FT_Select_Charmap(face, latin_encodings[ee]);
        if (!error)
            break;
    }

    if (!error)
    {
        /* For now, compute the standard width and height from the `o'. */
        af_latin_metrics_init_widths(metrics, face, 'o');
        af_latin_metrics_init_blues(metrics, face);
        af_latin_metrics_check_digits(metrics, face);
    }

    FT_Set_Charmap(face, oldmap);
    return AF_Err_Ok;
}


static void
af_latin_metrics_scale_dim(AF_LatinMetrics metrics,
                           AF_Scaler scaler,
                           AF_Dimension dim)
{
    FT_Fixed scale;
    FT_Pos delta;
    AF_LatinAxis axis;
    FT_UInt nn;


    if (dim == AF_DIMENSION_HORZ)
    {
        scale = scaler->x_scale;
        delta = scaler->x_delta;
    }
    else
    {
        scale = scaler->y_scale;
        delta = scaler->y_delta;
    }

    axis = &metrics->axis[dim];

    if (axis->org_scale == scale && axis->org_delta == delta)
        return;

    axis->org_scale = scale;
    axis->org_delta = delta;

    /*
     * correct X and Y scale to optimize the alignment of the top of small
     * letters to the pixel grid
     */
    {
        AF_LatinAxis Axis = &metrics->axis[AF_DIMENSION_VERT];
        AF_LatinBlue blue = NULL;


        for (nn = 0; nn < Axis->blue_count; nn++)
        {
            if (Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT)
            {
                blue = &Axis->blues[nn];
                break;
            }
        }

        if (blue)
        {
            FT_Pos scaled = FT_MulFix(blue->shoot.org, scaler->y_scale);
            FT_Pos fitted = (scaled + 40) & ~63;


            if (scaled != fitted)
            {
                #if 0
                if (dim == AF_DIMENSION_HORZ)
                {
                    if (fitted < scaled)
                        scale -= scale / 50; /* scale *= 0.98 */
                }
                else
                #endif
                if (dim == AF_DIMENSION_VERT)
                {
                    scale = FT_MulDiv(scale, fitted, scaled);
                }
            }
        }
    }

    axis->scale = scale;
    axis->delta = delta;

    if (dim == AF_DIMENSION_HORZ)
    {
        metrics->root.scaler.x_scale = scale;
        metrics->root.scaler.x_delta = delta;
    }
    else
    {
        metrics->root.scaler.y_scale = scale;
        metrics->root.scaler.y_delta = delta;
    }

    /* scale the standard widths */
    for (nn = 0; nn < axis->width_count; nn++)
    {
        AF_Width width = axis->widths + nn;


        width->cur = FT_MulFix(width->org, scale);
        width->fit = width->cur;
    }

    /* an extra-light axis corresponds to a standard width that is */
    /* smaller than 0.75 pixels                                    */
    axis->extra_light =
        (FT_Bool)(FT_MulFix(axis->standard_width, scale) < 32 + 8);

    if (dim == AF_DIMENSION_VERT)
    {
        /* scale the blue zones */
        for (nn = 0; nn < axis->blue_count; nn++)
        {
            AF_LatinBlue blue = &axis->blues[nn];
            FT_Pos dist;


            blue->ref.cur = FT_MulFix(blue->ref.org, scale) + delta;
            blue->ref.fit = blue->ref.cur;
            blue->shoot.cur = FT_MulFix(blue->shoot.org, scale) + delta;
            blue->shoot.fit = blue->shoot.cur;
            blue->flags &= ~AF_LATIN_BLUE_ACTIVE;

            /* a blue zone is only active if it is less than 3/4 pixels tall */
            dist = FT_MulFix(blue->ref.org - blue->shoot.org, scale);
            if (dist <= 48 && dist >= -48)
            {
                FT_Pos delta1, delta2;


                delta1 = blue->shoot.org - blue->ref.org;
                delta2 = delta1;
                if (delta1 < 0)
                    delta2 = -delta2;

                delta2 = FT_MulFix(delta2, scale);

                if (delta2 < 32)
                    delta2 = 0;
                else if (delta2 < 64)
                    delta2 = 32 + (((delta2 - 32) + 16) & ~31);
                else
                    delta2 = FT_PIX_ROUND(delta2);

                if (delta1 < 0)
                    delta2 = -delta2;

                blue->ref.fit = FT_PIX_ROUND(blue->ref.cur);
                blue->shoot.fit = blue->ref.fit + delta2;

                blue->flags |= AF_LATIN_BLUE_ACTIVE;
            }
        }
    }
}


FT_LOCAL_DEF(void)
af_latin_metrics_scale(AF_LatinMetrics metrics,
                       AF_Scaler scaler)
{
    metrics->root.scaler.render_mode = scaler->render_mode;
    metrics->root.scaler.face = scaler->face;

    af_latin_metrics_scale_dim(metrics, scaler, AF_DIMENSION_HORZ);
    af_latin_metrics_scale_dim(metrics, scaler, AF_DIMENSION_VERT);
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****           L A T I N   G L Y P H   A N A L Y S I S             *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/

FT_LOCAL_DEF(FT_Error)
af_latin_hints_compute_segments(AF_GlyphHints hints,
                                AF_Dimension dim)
{
    AF_AxisHints axis = &hints->axis[dim];
    FT_Memory memory = hints->memory;
    FT_Error error = AF_Err_Ok;
    AF_Segment segment = NULL;
    AF_SegmentRec seg0;
    AF_Point* contour = hints->contours;
    AF_Point* contour_limit = contour + hints->num_contours;
    AF_Direction major_dir, segment_dir;


    FT_ZERO(&seg0);
    seg0.score = 32000;
    seg0.flags = AF_EDGE_NORMAL;

    major_dir = (AF_Direction)FT_ABS(axis->major_dir);
    segment_dir = major_dir;

    axis->num_segments = 0;

    /* set up (u,v) in each point */
    if (dim == AF_DIMENSION_HORZ)
    {
        AF_Point point = hints->points;
        AF_Point limit = point + hints->num_points;


        for (; point < limit; point++)
        {
            point->u = point->fx;
            point->v = point->fy;
        }
    }
    else
    {
        AF_Point point = hints->points;
        AF_Point limit = point + hints->num_points;


        for (; point < limit; point++)
        {
            point->u = point->fy;
            point->v = point->fx;
        }
    }

    /* do each contour separately */
    for (; contour < contour_limit; contour++)
    {
        AF_Point point = contour[0];
        AF_Point last = point->prev;
        int on_edge = 0;
        FT_Pos min_pos = 32000;    /* minimum segment pos != min_coord */
        FT_Pos max_pos = -32000;   /* maximum segment pos != max_coord */
        FT_Bool passed;


        if (point == last)  /* skip singletons -- just in case */
            continue;

        if (FT_ABS(last->out_dir) == major_dir &&
            FT_ABS(point->out_dir) == major_dir)
        {
            /* we are already on an edge, try to locate its start */
            last = point;

            for (;;)
            {
                point = point->prev;
                if (FT_ABS(point->out_dir) != major_dir)
                {
                    point = point->next;
                    break;
                }
                if (point == last)
                    break;
            }
        }

        last = point;
        passed = 0;

        for (;;)
        {
            FT_Pos u, v;


            if (on_edge)
            {
                u = point->u;
                if (u < min_pos)
                    min_pos = u;
                if (u > max_pos)
                    max_pos = u;

                if (point->out_dir != segment_dir || point == last)
                {
                    /* we are just leaving an edge; record a new segment! */
                    segment->last = point;
                    segment->pos = (FT_Short)((min_pos + max_pos) >> 1);

                    /* a segment is round if either its first or last point */
                    /* is a control point                                   */
                    if ((segment->first->flags | point->flags) &
                        AF_FLAG_CONTROL)
                        segment->flags |= AF_EDGE_ROUND;

                    /* compute segment size */
                    min_pos = max_pos = point->v;

                    v = segment->first->v;
                    if (v < min_pos)
                        min_pos = v;
                    if (v > max_pos)
                        max_pos = v;

                    segment->min_coord = (FT_Short)min_pos;
                    segment->max_coord = (FT_Short)max_pos;
                    segment->height = (FT_Short)(segment->max_coord -
                                                 segment->min_coord);

                    on_edge = 0;
                    segment = NULL;
                    /* fallthrough */
                }
            }

            /* now exit if we are at the start/end point */
            if (point == last)
            {
                if (passed)
                    break;
                passed = 1;
            }

            if (!on_edge && FT_ABS(point->out_dir) == major_dir)
            {
                /* this is the start of a new segment! */
                segment_dir = (AF_Direction)point->out_dir;

                /* clear all segment fields */
                error = af_axis_hints_new_segment(axis, memory, &segment);
                if (error)
                    goto Exit;

                segment[0] = seg0;
                segment->dir = (FT_Char)segment_dir;
                min_pos = max_pos = point->u;
                segment->first = point;
                segment->last = point;
                segment->contour = contour;
                on_edge = 1;
            }

            point = point->next;
        }

    } /* contours */


    /* now slightly increase the height of segments when this makes */
    /* sense -- this is used to better detect and ignore serifs     */
    {
        AF_Segment segments = axis->segments;
        AF_Segment segments_end = segments + axis->num_segments;


        for (segment = segments; segment < segments_end; segment++)
        {
            AF_Point first = segment->first;
            AF_Point last = segment->last;
            FT_Pos first_v = first->v;
            FT_Pos last_v = last->v;


            if (first == last)
                continue;

            if (first_v < last_v)
            {
                AF_Point p;


                p = first->prev;
                if (p->v < first_v)
                    segment->height = (FT_Short)(segment->height +
                                                 ((first_v - p->v) >> 1));

                p = last->next;
                if (p->v > last_v)
                    segment->height = (FT_Short)(segment->height +
                                                 ((p->v - last_v) >> 1));
            }
            else
            {
                AF_Point p;


                p = first->prev;
                if (p->v > first_v)
                    segment->height = (FT_Short)(segment->height +
                                                 ((p->v - first_v) >> 1));

                p = last->next;
                if (p->v < last_v)
                    segment->height = (FT_Short)(segment->height +
                                                 ((last_v - p->v) >> 1));
            }
        }
    }

Exit:
    return error;
}


FT_LOCAL_DEF(void)
af_latin_hints_link_segments(AF_GlyphHints hints,
                             AF_Dimension dim)
{
    AF_AxisHints axis = &hints->axis[dim];
    AF_Segment segments = axis->segments;
    AF_Segment segment_limit = segments + axis->num_segments;
    FT_Pos len_threshold, len_score;
    AF_Segment seg1, seg2;


    len_threshold = AF_LATIN_CONSTANT(hints->metrics, 8);
    if (len_threshold == 0)
        len_threshold = 1;

    len_score = AF_LATIN_CONSTANT(hints->metrics, 6000);

    /* now compare each segment to the others */
    for (seg1 = segments; seg1 < segment_limit; seg1++)
    {
        /* the fake segments are introduced to hint the metrics -- */
        /* we must never link them to anything                     */
        if (seg1->dir != axis->major_dir || seg1->first == seg1->last)
            continue;

        for (seg2 = segments; seg2 < segment_limit; seg2++)
            if (seg1->dir + seg2->dir == 0 && seg2->pos > seg1->pos)
            {
                FT_Pos pos1 = seg1->pos;
                FT_Pos pos2 = seg2->pos;
                FT_Pos dist = pos2 - pos1;


                if (dist < 0)
                    dist = -dist;

                {
                    FT_Pos min = seg1->min_coord;
                    FT_Pos max = seg1->max_coord;
                    FT_Pos len, score;


                    if (min < seg2->min_coord)
                        min = seg2->min_coord;

                    if (max > seg2->max_coord)
                        max = seg2->max_coord;

                    len = max - min;
                    if (len >= len_threshold)
                    {
                        score = dist + len_score / len;

                        if (score < seg1->score)
                        {
                            seg1->score = score;
                            seg1->link = seg2;
                        }

                        if (score < seg2->score)
                        {
                            seg2->score = score;
                            seg2->link = seg1;
                        }
                    }
                }
            }
    }

    /* now, compute the `serif' segments */
    for (seg1 = segments; seg1 < segment_limit; seg1++)
    {
        seg2 = seg1->link;

        if (seg2)
        {
            if (seg2->link != seg1)
            {
                seg1->link = 0;
                seg1->serif = seg2->link;
            }
        }
    }
}


FT_LOCAL_DEF(FT_Error)
af_latin_hints_compute_edges(AF_GlyphHints hints,
                             AF_Dimension dim)
{
    AF_AxisHints axis = &hints->axis[dim];
    FT_Error error = AF_Err_Ok;
    FT_Memory memory = hints->memory;
    AF_LatinAxis laxis = &((AF_LatinMetrics)hints->metrics)->axis[dim];

    AF_Segment segments = axis->segments;
    AF_Segment segment_limit = segments + axis->num_segments;
    AF_Segment seg;

    AF_Direction up_dir;
    FT_Fixed scale;
    FT_Pos edge_distance_threshold;
    FT_Pos segment_length_threshold;


    axis->num_edges = 0;

    scale = (dim == AF_DIMENSION_HORZ) ? hints->x_scale
            : hints->y_scale;

    up_dir = (dim == AF_DIMENSION_HORZ) ? AF_DIR_UP
             : AF_DIR_RIGHT;

    /*
     *  We ignore all segments that are less than 1 pixels in length,
     *  to avoid many problems with serif fonts.  We compute the
     *  corresponding threshold in font units.
     */
    if (dim == AF_DIMENSION_HORZ)
        segment_length_threshold = FT_DivFix(64, hints->y_scale);
    else
        segment_length_threshold = 0;

    /*********************************************************************/
    /*                                                                   */
    /* We will begin by generating a sorted table of edges for the       */
    /* current direction.  To do so, we simply scan each segment and try */
    /* to find an edge in our table that corresponds to its position.    */
    /*                                                                   */
    /* If no edge is found, we create and insert a new edge in the       */
    /* sorted table.  Otherwise, we simply add the segment to the edge's */
    /* list which will be processed in the second step to compute the    */
    /* edge's properties.                                                */
    /*                                                                   */
    /* Note that the edges table is sorted along the segment/edge        */
    /* position.                                                         */
    /*                                                                   */
    /*********************************************************************/

    edge_distance_threshold = FT_MulFix(laxis->edge_distance_threshold,
                                        scale);
    if (edge_distance_threshold > 64 / 4)
        edge_distance_threshold = 64 / 4;

    edge_distance_threshold = FT_DivFix(edge_distance_threshold,
                                        scale);

    for (seg = segments; seg < segment_limit; seg++)
    {
        AF_Edge found = 0;
        FT_Int ee;


        if (seg->height < segment_length_threshold)
            continue;

        /* A special case for serif edges: If they are smaller than */
        /* 1.5 pixels we ignore them.                               */
        if (seg->serif &&
            2 * seg->height < 3 * segment_length_threshold)
            continue;

        /* look for an edge corresponding to the segment */
        for (ee = 0; ee < axis->num_edges; ee++)
        {
            AF_Edge edge = axis->edges + ee;
            FT_Pos dist;


            dist = seg->pos - edge->fpos;
            if (dist < 0)
                dist = -dist;

            if (dist < edge_distance_threshold && edge->dir == seg->dir)
            {
                found = edge;
                break;
            }
        }

        if (!found)
        {
            AF_Edge edge;


            /* insert a new edge in the list and */
            /* sort according to the position    */
            error = af_axis_hints_new_edge(axis, seg->pos,
                                           (AF_Direction)seg->dir,
                                           memory, &edge);
            if (error)
                goto Exit;

            /* add the segment to the new edge's list */
            FT_ZERO(edge);

            edge->first = seg;
            edge->last = seg;
            edge->fpos = seg->pos;
            edge->dir = seg->dir;
            edge->opos = edge->pos = FT_MulFix(seg->pos, scale);
            seg->edge_next = seg;
        }
        else
        {
            /* if an edge was found, simply add the segment to the edge's */
            /* list                                                       */
            seg->edge_next = found->first;
            found->last->edge_next = seg;
            found->last = seg;
        }
    }


    /*********************************************************************/
    /*                                                                   */
    /* Good, we will now compute each edge's properties according to     */
    /* segments found on its position.  Basically, these are:            */
    /*                                                                   */
    /*  - edge's main direction                                          */
    /*  - stem edge, serif edge or both (which defaults to stem then)    */
    /*  - rounded edge, straight or both (which defaults to straight)    */
    /*  - link for edge                                                  */
    /*                                                                   */
    /*********************************************************************/

    /* first of all, set the `edge' field in each segment -- this is */
    /* required in order to compute edge links                       */

    /*
     * Note that removing this loop and setting the `edge' field of each
     * segment directly in the code above slows down execution speed for
     * some reasons on platforms like the Sun.
     */
    {
        AF_Edge edges = axis->edges;
        AF_Edge edge_limit = edges + axis->num_edges;
        AF_Edge edge;


        for (edge = edges; edge < edge_limit; edge++)
        {
            seg = edge->first;
            if (seg)
                do
                {
                    seg->edge = edge;
                    seg = seg->edge_next;

                }
                while (seg != edge->first);
        }

        /* now, compute each edge properties */
        for (edge = edges; edge < edge_limit; edge++)
        {
            FT_Int is_round = 0;  /* does it contain round segments?    */
            FT_Int is_straight = 0; /* does it contain straight segments? */
            FT_Pos ups = 0;       /* number of upwards segments         */
            FT_Pos downs = 0;     /* number of downwards segments       */


            seg = edge->first;

            do
            {
                FT_Bool is_serif;


                /* check for roundness of segment */
                if (seg->flags & AF_EDGE_ROUND)
                    is_round++;
                else
                    is_straight++;

                /* check for segment direction */
                if (seg->dir == up_dir)
                    ups += seg->max_coord - seg->min_coord;
                else
                    downs += seg->max_coord - seg->min_coord;

                /* check for links -- if seg->serif is set, then seg->link must */
                /* be ignored                                                   */
                is_serif = (FT_Bool)(seg->serif &&
                                     seg->serif->edge &&
                                     seg->serif->edge != edge);

                if ((seg->link && seg->link->edge != NULL) || is_serif)
                {
                    AF_Edge edge2;
                    AF_Segment seg2;


                    edge2 = edge->link;
                    seg2 = seg->link;

                    if (is_serif)
                    {
                        seg2 = seg->serif;
                        edge2 = edge->serif;
                    }

                    if (edge2)
                    {
                        FT_Pos edge_delta;
                        FT_Pos seg_delta;


                        edge_delta = edge->fpos - edge2->fpos;
                        if (edge_delta < 0)
                            edge_delta = -edge_delta;

                        seg_delta = seg->pos - seg2->pos;
                        if (seg_delta < 0)
                            seg_delta = -seg_delta;

                        if (seg_delta < edge_delta)
                            edge2 = seg2->edge;
                    }
                    else
                        edge2 = seg2->edge;

                    if (is_serif)
                    {
                        edge->serif = edge2;
                        edge2->flags |= AF_EDGE_SERIF;
                    }
                    else
                        edge->link = edge2;
                }

                seg = seg->edge_next;

            }
            while (seg != edge->first);

            /* set the round/straight flags */
            edge->flags = AF_EDGE_NORMAL;

            if (is_round > 0 && is_round >= is_straight)
                edge->flags |= AF_EDGE_ROUND;

            #if 0
            /* set the edge's main direction */
            edge->dir = AF_DIR_NONE;

            if (ups > downs)
                edge->dir = (FT_Char)up_dir;

            else if (ups < downs)
                edge->dir = (FT_Char) - up_dir;

            else if (ups == downs)
                edge->dir = 0; /* both up and down! */
            #endif

            /* gets rid of serifs if link is set                */
            /* XXX: This gets rid of many unpleasant artefacts! */
            /*      Example: the `c' in cour.pfa at size 13     */

            if (edge->serif && edge->link)
                edge->serif = 0;
        }
    }

Exit:
    return error;
}


FT_LOCAL_DEF(FT_Error)
af_latin_hints_detect_features(AF_GlyphHints hints,
                               AF_Dimension dim)
{
    FT_Error error;


    error = af_latin_hints_compute_segments(hints, dim);
    if (!error)
    {
        af_latin_hints_link_segments(hints, dim);

        error = af_latin_hints_compute_edges(hints, dim);
    }
    return error;
}


FT_LOCAL_DEF(void)
af_latin_hints_compute_blue_edges(AF_GlyphHints hints,
                                  AF_LatinMetrics metrics)
{
    AF_AxisHints axis = &hints->axis[AF_DIMENSION_VERT];
    AF_Edge edge = axis->edges;
    AF_Edge edge_limit = edge + axis->num_edges;
    AF_LatinAxis latin = &metrics->axis[AF_DIMENSION_VERT];
    FT_Fixed scale = latin->scale;


    /* compute which blue zones are active, i.e. have their scaled */
    /* size < 3/4 pixels                                           */

    /* for each horizontal edge search the blue zone which is closest */
    for (; edge < edge_limit; edge++)
    {
        FT_Int bb;
        AF_Width best_blue = NULL;
        FT_Pos best_dist;   /* initial threshold */


        /* compute the initial threshold as a fraction of the EM size */
        best_dist = FT_MulFix(metrics->units_per_em / 40, scale);

        if (best_dist > 64 / 2)
            best_dist = 64 / 2;

        for (bb = 0; bb < AF_LATIN_BLUE_MAX; bb++)
        {
            AF_LatinBlue blue = latin->blues + bb;
            FT_Bool is_top_blue, is_major_dir;


            /* skip inactive blue zones (i.e., those that are too small) */
            if (!(blue->flags & AF_LATIN_BLUE_ACTIVE))
                continue;

            /* if it is a top zone, check for right edges -- if it is a bottom */
            /* zone, check for left edges                                      */
            /*                                                                 */
            /* of course, that's for TrueType                                  */
            is_top_blue = (FT_Byte)((blue->flags & AF_LATIN_BLUE_TOP) != 0);
            is_major_dir = FT_BOOL(edge->dir == axis->major_dir);

            /* if it is a top zone, the edge must be against the major    */
            /* direction; if it is a bottom zone, it must be in the major */
            /* direction                                                  */
            if (is_top_blue ^ is_major_dir)
            {
                FT_Pos dist;


                /* first of all, compare it to the reference position */
                dist = edge->fpos - blue->ref.org;
                if (dist < 0)
                    dist = -dist;

                dist = FT_MulFix(dist, scale);
                if (dist < best_dist)
                {
                    best_dist = dist;
                    best_blue = &blue->ref;
                }

                /* now, compare it to the overshoot position if the edge is     */
                /* rounded, and if the edge is over the reference position of a */
                /* top zone, or under the reference position of a bottom zone   */
                if (edge->flags & AF_EDGE_ROUND && dist != 0)
                {
                    FT_Bool is_under_ref = FT_BOOL(edge->fpos < blue->ref.org);


                    if (is_top_blue ^ is_under_ref)
                    {
                        blue = latin->blues + bb;
                        dist = edge->fpos - blue->shoot.org;
                        if (dist < 0)
                            dist = -dist;

                        dist = FT_MulFix(dist, scale);
                        if (dist < best_dist)
                        {
                            best_dist = dist;
                            best_blue = &blue->shoot;
                        }
                    }
                }
            }
        }

        if (best_blue)
            edge->blue_edge = best_blue;
    }
}


static FT_Error
af_latin_hints_init(AF_GlyphHints hints,
                    AF_LatinMetrics metrics)
{
    FT_Render_Mode mode;
    FT_UInt32 scaler_flags, other_flags;
    FT_Face face = metrics->root.scaler.face;


    af_glyph_hints_rescale(hints, (AF_ScriptMetrics)metrics);

    /*
     *  correct x_scale and y_scale if needed, since they may have
     *  been modified `af_latin_metrics_scale_dim' above
     */
    hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale;
    hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta;
    hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale;
    hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta;

    /* compute flags depending on render mode, etc. */
    mode = metrics->root.scaler.render_mode;

    #if 0 /* #ifdef AF_USE_WARPER */
    if (mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V)
    {
        metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL;
    }
    #endif

    scaler_flags = hints->scaler_flags;
    other_flags = 0;

    /*
     *  We snap the width of vertical stems for the monochrome and
     *  horizontal LCD rendering targets only.
     */
    if (mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD)
        other_flags |= AF_LATIN_HINTS_HORZ_SNAP;

    /*
     *  We snap the width of horizontal stems for the monochrome and
     *  vertical LCD rendering targets only.
     */
    if (mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V)
        other_flags |= AF_LATIN_HINTS_VERT_SNAP;

    /*
     *  We adjust stems to full pixels only if we don't use the `light' mode.
     */
    if (mode != FT_RENDER_MODE_LIGHT)
        other_flags |= AF_LATIN_HINTS_STEM_ADJUST;

    if (mode == FT_RENDER_MODE_MONO)
        other_flags |= AF_LATIN_HINTS_MONO;

    /*
     *  In `light' hinting mode we disable horizontal hinting completely.
     *  We also do it if the face is italic.
     */
    if (mode == FT_RENDER_MODE_LIGHT ||
        (face->style_flags & FT_STYLE_FLAG_ITALIC) != 0)
        scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL;

    hints->scaler_flags = scaler_flags;
    hints->other_flags = other_flags;

    return 0;
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****        L A T I N   G L Y P H   G R I D - F I T T I N G        *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/

/* snap a given width in scaled coordinates to one of the */
/* current standard widths                                */

static FT_Pos
af_latin_snap_width(AF_Width widths,
                    FT_Int count,
                    FT_Pos width)
{
    int n;
    FT_Pos best = 64 + 32 + 2;
    FT_Pos reference = width;
    FT_Pos scaled;


    for (n = 0; n < count; n++)
    {
        FT_Pos w;
        FT_Pos dist;


        w = widths[n].cur;
        dist = width - w;
        if (dist < 0)
            dist = -dist;
        if (dist < best)
        {
            best = dist;
            reference = w;
        }
    }

    scaled = FT_PIX_ROUND(reference);

    if (width >= reference)
    {
        if (width < scaled + 48)
            width = reference;
    }
    else
    {
        if (width > scaled - 48)
            width = reference;
    }

    return width;
}


/* compute the snapped width of a given stem */

static FT_Pos
af_latin_compute_stem_width(AF_GlyphHints hints,
                            AF_Dimension dim,
                            FT_Pos width,
                            AF_Edge_Flags base_flags,
                            AF_Edge_Flags stem_flags)
{
    AF_LatinMetrics metrics = (AF_LatinMetrics)hints->metrics;
    AF_LatinAxis axis = &metrics->axis[dim];
    FT_Pos dist = width;
    FT_Int sign = 0;
    FT_Int vertical = (dim == AF_DIMENSION_VERT);


    if (!AF_LATIN_HINTS_DO_STEM_ADJUST(hints) ||
        axis->extra_light)
        return width;

    if (dist < 0)
    {
        dist = -width;
        sign = 1;
    }

    if ((vertical && !AF_LATIN_HINTS_DO_VERT_SNAP(hints)) ||
        (!vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP(hints)))
    {
        /* smooth hinting process: very lightly quantize the stem width */

        /* leave the widths of serifs alone */

        if ((stem_flags & AF_EDGE_SERIF) && vertical && (dist < 3 * 64))
            goto Done_Width;

        else if ((base_flags & AF_EDGE_ROUND))
        {
            if (dist < 80)
                dist = 64;
        }
        else if (dist < 56)
            dist = 56;

        if (axis->width_count > 0)
        {
            FT_Pos delta;


            /* compare to standard width */
            if (axis->width_count > 0)
            {
                delta = dist - axis->widths[0].cur;

                if (delta < 0)
                    delta = -delta;

                if (delta < 40)
                {
                    dist = axis->widths[0].cur;
                    if (dist < 48)
                        dist = 48;

                    goto Done_Width;
                }
            }

            if (dist < 3 * 64)
            {
                delta = dist & 63;
                dist &= -64;

                if (delta < 10)
                    dist += delta;

                else if (delta < 32)
                    dist += 10;

                else if (delta < 54)
                    dist += 54;

                else
                    dist += delta;
            }
            else
                dist = (dist + 32) & ~63;
        }
    }
    else
    {
        /* strong hinting process: snap the stem width to integer pixels */
        FT_Pos org_dist = dist;


        dist = af_latin_snap_width(axis->widths, axis->width_count, dist);

        if (vertical)
        {
            /* in the case of vertical hinting, always round */
            /* the stem heights to integer pixels            */

            if (dist >= 64)
                dist = (dist + 16) & ~63;
            else
                dist = 64;
        }
        else
        {
            if (AF_LATIN_HINTS_DO_MONO(hints))
            {
                /* monochrome horizontal hinting: snap widths to integer pixels */
                /* with a different threshold                                   */

                if (dist < 64)
                    dist = 64;
                else
                    dist = (dist + 32) & ~63;
            }
            else
            {
                /* for horizontal anti-aliased hinting, we adopt a more subtle */
                /* approach: we strengthen small stems, round stems whose size */
                /* is between 1 and 2 pixels to an integer, otherwise nothing  */

                if (dist < 48)
                    dist = (dist + 64) >> 1;

                else if (dist < 128)
                {
                    /* We only round to an integer width if the corresponding */
                    /* distortion is less than 1/4 pixel.  Otherwise this     */
                    /* makes everything worse since the diagonals, which are  */
                    /* not hinted, appear a lot bolder or thinner than the    */
                    /* vertical stems.                                        */

                    FT_Pos delta;


                    dist = (dist + 22) & ~63;
                    delta = dist - org_dist;
                    if (delta < 0)
                        delta = -delta;

                    if (delta >= 16)
                    {
                        dist = org_dist;
                        if (dist < 48)
                            dist = (dist + 64) >> 1;
                    }
                }
                else
                    /* round otherwise to prevent color fringes in LCD mode */
                    dist = (dist + 32) & ~63;
            }
        }
    }

Done_Width:
    if (sign)
        dist = -dist;

    return dist;
}


/* align one stem edge relative to the previous stem edge */

static void
af_latin_align_linked_edge(AF_GlyphHints hints,
                           AF_Dimension dim,
                           AF_Edge base_edge,
                           AF_Edge stem_edge)
{
    FT_Pos dist = stem_edge->opos - base_edge->opos;

    FT_Pos fitted_width = af_latin_compute_stem_width(
        hints, dim, dist,
        (AF_Edge_Flags)base_edge->flags,
        (AF_Edge_Flags)stem_edge->flags);


    stem_edge->pos = base_edge->pos + fitted_width;

    AF_LOG(("LINK: edge %d (opos=%.2f) linked to (%.2f), "
            "dist was %.2f, now %.2f\n",
            stem_edge - hints->axis[dim].edges, stem_edge->opos / 64.0,
            stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0));
}


static void
af_latin_align_serif_edge(AF_GlyphHints hints,
                          AF_Edge base,
                          AF_Edge serif)
{
    FT_UNUSED(hints);

    serif->pos = base->pos + (serif->opos - base->opos);
}


/*************************************************************************/
/*************************************************************************/
/*************************************************************************/
/****                                                                 ****/
/****                    E D G E   H I N T I N G                      ****/
/****                                                                 ****/
/*************************************************************************/
/*************************************************************************/
/*************************************************************************/


FT_LOCAL_DEF(void)
af_latin_hint_edges(AF_GlyphHints hints,
                    AF_Dimension dim)
{
    AF_AxisHints axis = &hints->axis[dim];
    AF_Edge edges = axis->edges;
    AF_Edge edge_limit = edges + axis->num_edges;
    FT_PtrDist n_edges;
    AF_Edge edge;
    AF_Edge anchor = 0;
    FT_Int has_serifs = 0;


    /* we begin by aligning all stems relative to the blue zone */
    /* if needed -- that's only for horizontal edges            */

    if (dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES(hints))
    {
        for (edge = edges; edge < edge_limit; edge++)
        {
            AF_Width blue;
            AF_Edge edge1, edge2;


            if (edge->flags & AF_EDGE_DONE)
                continue;

            blue = edge->blue_edge;
            edge1 = NULL;
            edge2 = edge->link;

            if (blue)
            {
                edge1 = edge;
            }
            else if (edge2 && edge2->blue_edge)
            {
                blue = edge2->blue_edge;
                edge1 = edge2;
                edge2 = edge;
            }

            if (!edge1)
                continue;

            AF_LOG(("BLUE: edge %d (opos=%.2f) snapped to (%.2f), "
                    "was (%.2f)\n",
                    edge1 - edges, edge1->opos / 64.0, blue->fit / 64.0,
                    edge1->pos / 64.0));

            edge1->pos = blue->fit;
            edge1->flags |= AF_EDGE_DONE;

            if (edge2 && !edge2->blue_edge)
            {
                af_latin_align_linked_edge(hints, dim, edge1, edge2);
                edge2->flags |= AF_EDGE_DONE;
            }

            if (!anchor)
                anchor = edge;
        }
    }

    /* now we will align all stem edges, trying to maintain the */
    /* relative order of stems in the glyph                     */
    for (edge = edges; edge < edge_limit; edge++)
    {
        AF_Edge edge2;


        if (edge->flags & AF_EDGE_DONE)
            continue;

        /* skip all non-stem edges */
        edge2 = edge->link;
        if (!edge2)
        {
            has_serifs++;
            continue;
        }

        /* now align the stem */

        /* this should not happen, but it's better to be safe */
        if (edge2->blue_edge)
        {
            AF_LOG(("ASSERTION FAILED for edge %d\n", edge2 - edges));

            af_latin_align_linked_edge(hints, dim, edge2, edge);
            edge->flags |= AF_EDGE_DONE;
            continue;
        }

        if (!anchor)
        {
            FT_Pos org_len, org_center, cur_len;
            FT_Pos cur_pos1, error1, error2, u_off, d_off;


            org_len = edge2->opos - edge->opos;
            cur_len = af_latin_compute_stem_width(
                hints, dim, org_len,
                (AF_Edge_Flags)edge->flags,
                (AF_Edge_Flags)edge2->flags);
            if (cur_len <= 64)
                u_off = d_off = 32;
            else
            {
                u_off = 38;
                d_off = 26;
            }

            if (cur_len < 96)
            {
                org_center = edge->opos + (org_len >> 1);

                cur_pos1 = FT_PIX_ROUND(org_center);

                error1 = org_center - (cur_pos1 - u_off);
                if (error1 < 0)
                    error1 = -error1;

                error2 = org_center - (cur_pos1 + d_off);
                if (error2 < 0)
                    error2 = -error2;

                if (error1 < error2)
                    cur_pos1 -= u_off;
                else
                    cur_pos1 += d_off;

                edge->pos = cur_pos1 - cur_len / 2;
                edge2->pos = edge->pos + cur_len;
            }
            else
                edge->pos = FT_PIX_ROUND(edge->opos);

            AF_LOG(("ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f) "
                    "snapped to (%.2f) (%.2f)\n",
                    edge - edges, edge->opos / 64.0,
                    edge2 - edges, edge2->opos / 64.0,
                    edge->pos / 64.0, edge2->pos / 64.0));
            anchor = edge;

            edge->flags |= AF_EDGE_DONE;

            af_latin_align_linked_edge(hints, dim, edge, edge2);
        }
        else
        {
            FT_Pos org_pos, org_len, org_center, cur_len;
            FT_Pos cur_pos1, cur_pos2, delta1, delta2;


            org_pos = anchor->pos + (edge->opos - anchor->opos);
            org_len = edge2->opos - edge->opos;
            org_center = org_pos + (org_len >> 1);

            cur_len = af_latin_compute_stem_width(
                hints, dim, org_len,
                (AF_Edge_Flags)edge->flags,
                (AF_Edge_Flags)edge2->flags);

            if (edge2->flags & AF_EDGE_DONE)
                edge->pos = edge2->pos - cur_len;

            else if (cur_len < 96)
            {
                FT_Pos u_off, d_off;


                cur_pos1 = FT_PIX_ROUND(org_center);

                if (cur_len <= 64)
                    u_off = d_off = 32;
                else
                {
                    u_off = 38;
                    d_off = 26;
                }

                delta1 = org_center - (cur_pos1 - u_off);
                if (delta1 < 0)
                    delta1 = -delta1;

                delta2 = org_center - (cur_pos1 + d_off);
                if (delta2 < 0)
                    delta2 = -delta2;

                if (delta1 < delta2)
                    cur_pos1 -= u_off;
                else
                    cur_pos1 += d_off;

                edge->pos = cur_pos1 - cur_len / 2;
                edge2->pos = cur_pos1 + cur_len / 2;

                AF_LOG(("STEM: %d (opos=%.2f) to %d (opos=%.2f) "
                        "snapped to (%.2f) and (%.2f)\n",
                        edge - edges, edge->opos / 64.0,
                        edge2 - edges, edge2->opos / 64.0,
                        edge->pos / 64.0, edge2->pos / 64.0));
            }
            else
            {
                org_pos = anchor->pos + (edge->opos - anchor->opos);
                org_len = edge2->opos - edge->opos;
                org_center = org_pos + (org_len >> 1);

                cur_len = af_latin_compute_stem_width(
                    hints, dim, org_len,
                    (AF_Edge_Flags)edge->flags,
                    (AF_Edge_Flags)edge2->flags);

                cur_pos1 = FT_PIX_ROUND(org_pos);
                delta1 = cur_pos1 + (cur_len >> 1) - org_center;
                if (delta1 < 0)
                    delta1 = -delta1;

                cur_pos2 = FT_PIX_ROUND(org_pos + org_len) - cur_len;
                delta2 = cur_pos2 + (cur_len >> 1) - org_center;
                if (delta2 < 0)
                    delta2 = -delta2;

                edge->pos = (delta1 < delta2) ? cur_pos1 : cur_pos2;
                edge2->pos = edge->pos + cur_len;

                AF_LOG(("STEM: %d (opos=%.2f) to %d (opos=%.2f) "
                        "snapped to (%.2f) and (%.2f)\n",
                        edge - edges, edge->opos / 64.0,
                        edge2 - edges, edge2->opos / 64.0,
                        edge->pos / 64.0, edge2->pos / 64.0));
            }

            edge->flags |= AF_EDGE_DONE;
            edge2->flags |= AF_EDGE_DONE;

            if (edge > edges && edge->pos < edge[-1].pos)
            {
                AF_LOG(("BOUND: %d (pos=%.2f) to (%.2f)\n",
                        edge - edges, edge->pos / 64.0, edge[-1].pos / 64.0));
                edge->pos = edge[-1].pos;
            }
        }
    }

    /* make sure that lowercase m's maintain their symmetry */

    /* In general, lowercase m's have six vertical edges if they are sans */
    /* serif, or twelve if they are with serifs.  This implementation is  */
    /* based on that assumption, and seems to work very well with most    */
    /* faces.  However, if for a certain face this assumption is not      */
    /* true, the m is just rendered like before.  In addition, any stem   */
    /* correction will only be applied to symmetrical glyphs (even if the */
    /* glyph is not an m), so the potential for unwanted distortion is    */
    /* relatively low.                                                    */

    /* We don't handle horizontal edges since we can't easily assure that */
    /* the third (lowest) stem aligns with the base line; it might end up */
    /* one pixel higher or lower.                                         */

    n_edges = edge_limit - edges;
    if (dim == AF_DIMENSION_HORZ && (n_edges == 6 || n_edges == 12))
    {
        AF_Edge edge1, edge2, edge3;
        FT_Pos dist1, dist2, span, delta;


        if (n_edges == 6)
        {
            edge1 = edges;
            edge2 = edges + 2;
            edge3 = edges + 4;
        }
        else
        {
            edge1 = edges + 1;
            edge2 = edges + 5;
            edge3 = edges + 9;
        }

        dist1 = edge2->opos - edge1->opos;
        dist2 = edge3->opos - edge2->opos;

        span = dist1 - dist2;
        if (span < 0)
            span = -span;

        if (span < 8)
        {
            delta = edge3->pos - (2 * edge2->pos - edge1->pos);
            edge3->pos -= delta;
            if (edge3->link)
                edge3->link->pos -= delta;

            /* move the serifs along with the stem */
            if (n_edges == 12)
            {
                (edges + 8)->pos -= delta;
                (edges + 11)->pos -= delta;
            }

            edge3->flags |= AF_EDGE_DONE;
            if (edge3->link)
                edge3->link->flags |= AF_EDGE_DONE;
        }
    }

    if (has_serifs || !anchor)
    {
        /*
         *  now hint the remaining edges (serifs and single) in order
         *  to complete our processing
         */
        for (edge = edges; edge < edge_limit; edge++)
        {
            FT_Pos delta;


            if (edge->flags & AF_EDGE_DONE)
                continue;

            delta = 1000;

            if (edge->serif)
            {
                delta = edge->serif->opos - edge->opos;
                if (delta < 0)
                    delta = -delta;
            }

            if (delta < 64 + 16)
            {
                af_latin_align_serif_edge(hints, edge->serif, edge);
                AF_LOG(("SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f) "
                        "aligned to (%.2f)\n",
                        edge - edges, edge->opos / 64.0,
                        edge->serif - edges, edge->serif->opos / 64.0,
                        edge->pos / 64.0));
            }
            else if (!anchor)
            {
                AF_LOG(("SERIF_ANCHOR: edge %d (opos=%.2f) snapped to (%.2f)\n",
                        edge - edges, edge->opos / 64.0, edge->pos / 64.0));
                edge->pos = FT_PIX_ROUND(edge->opos);
                anchor = edge;
            }
            else
            {
                AF_Edge before, after;


                for (before = edge - 1; before >= edges; before--)
                    if (before->flags & AF_EDGE_DONE)
                        break;

                for (after = edge + 1; after < edge_limit; after++)
                    if (after->flags & AF_EDGE_DONE)
                        break;

                if (before >= edges && before < edge &&
                    after < edge_limit && after > edge)
                {
                    if (after->opos == before->opos)
                        edge->pos = before->pos;
                    else
                        edge->pos = before->pos +
                                    FT_MulDiv(edge->opos - before->opos,
                                              after->pos - before->pos,
                                              after->opos - before->opos);
                    AF_LOG(("SERIF_LINK1: edge %d (opos=%.2f) snapped to (%.2f) "
                            "from %d (opos=%.2f)\n",
                            edge - edges, edge->opos / 64.0,
                            edge->pos / 64.0, before - edges,
                            before->opos / 64.0));
                }
                else
                {
                    edge->pos = anchor->pos +
                                ((edge->opos - anchor->opos + 16) & ~31);
                    AF_LOG(("SERIF_LINK2: edge %d (opos=%.2f) snapped to (%.2f)\n",
                            edge - edges, edge->opos / 64.0, edge->pos / 64.0));
                }
            }

            edge->flags |= AF_EDGE_DONE;

            if (edge > edges && edge->pos < edge[-1].pos)
                edge->pos = edge[-1].pos;

            if (edge + 1 < edge_limit &&
                edge[1].flags & AF_EDGE_DONE &&
                edge->pos > edge[1].pos)
                edge->pos = edge[1].pos;
        }
    }
}


static FT_Error
af_latin_hints_apply(AF_GlyphHints hints,
                     FT_Outline* outline,
                     AF_LatinMetrics metrics)
{
    FT_Error error;
    int dim;


    error = af_glyph_hints_reload(hints, outline, 1);
    if (error)
        goto Exit;

    /* analyze glyph outline */
    #ifdef AF_USE_WARPER
    if (metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT ||
        AF_HINTS_DO_HORIZONTAL(hints))
    #else
    if (AF_HINTS_DO_HORIZONTAL(hints))
    #endif
    {
        error = af_latin_hints_detect_features(hints, AF_DIMENSION_HORZ);
        if (error)
            goto Exit;
    }

    if (AF_HINTS_DO_VERTICAL(hints))
    {
        error = af_latin_hints_detect_features(hints, AF_DIMENSION_VERT);
        if (error)
            goto Exit;

        af_latin_hints_compute_blue_edges(hints, metrics);
    }

    /* grid-fit the outline */
    for (dim = 0; dim < AF_DIMENSION_MAX; dim++)
    {
        #ifdef AF_USE_WARPER
        if ((dim == AF_DIMENSION_HORZ &&
             metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT))
        {
            AF_WarperRec warper;
            FT_Fixed scale;
            FT_Pos delta;


            af_warper_compute(&warper, hints, dim, &scale, &delta);
            af_glyph_hints_scale_dim(hints, dim, scale, delta);
            continue;
        }
        #endif

        if ((dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL(hints)) ||
            (dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL(hints)))
        {
            af_latin_hint_edges(hints, (AF_Dimension)dim);
            af_glyph_hints_align_edge_points(hints, (AF_Dimension)dim);
            af_glyph_hints_align_strong_points(hints, (AF_Dimension)dim);
            af_glyph_hints_align_weak_points(hints, (AF_Dimension)dim);
        }
    }
    af_glyph_hints_save(hints, outline);

Exit:
    return error;
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****              L A T I N   S C R I P T   C L A S S              *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/


/* XXX: this should probably fine tuned to differentiate better between */
/*      scripts...                                                      */

static const AF_Script_UniRangeRec af_latin_uniranges[] =
{
    AF_UNIRANGE_REC(0x0020UL, 0x007FUL),      /* Basic Latin (no control chars) */
    AF_UNIRANGE_REC(0x00A0UL, 0x00FFUL),      /* Latin-1 Supplement (no control chars) */
    AF_UNIRANGE_REC(0x0100UL, 0x017FUL),      /* Latin Extended-A */
    AF_UNIRANGE_REC(0x0180UL, 0x024FUL),      /* Latin Extended-B */
    AF_UNIRANGE_REC(0x0250UL, 0x02AFUL),      /* IPA Extensions */
    AF_UNIRANGE_REC(0x02B0UL, 0x02FFUL),      /* Spacing Modifier Letters */
    AF_UNIRANGE_REC(0x0300UL, 0x036FUL),      /* Combining Diacritical Marks */
    AF_UNIRANGE_REC(0x0370UL, 0x03FFUL),      /* Greek and Coptic */
    AF_UNIRANGE_REC(0x0400UL, 0x04FFUL),      /* Cyrillic */
    AF_UNIRANGE_REC(0x0500UL, 0x052FUL),      /* Cyrillic Supplement */
    AF_UNIRANGE_REC(0x1D00UL, 0x1D7FUL),      /* Phonetic Extensions */
    AF_UNIRANGE_REC(0x1D80UL, 0x1DBFUL),      /* Phonetic Extensions Supplement */
    AF_UNIRANGE_REC(0x1DC0UL, 0x1DFFUL),      /* Combining Diacritical Marks Supplement */
    AF_UNIRANGE_REC(0x1E00UL, 0x1EFFUL),      /* Latin Extended Additional */
    AF_UNIRANGE_REC(0x1F00UL, 0x1FFFUL),      /* Greek Extended */
    AF_UNIRANGE_REC(0x2000UL, 0x206FUL),      /* General Punctuation */
    AF_UNIRANGE_REC(0x2070UL, 0x209FUL),      /* Superscripts and Subscripts */
    AF_UNIRANGE_REC(0x20A0UL, 0x20CFUL),      /* Currency Symbols */
    AF_UNIRANGE_REC(0x2150UL, 0x218FUL),      /* Number Forms */
    AF_UNIRANGE_REC(0x2460UL, 0x24FFUL),      /* Enclosed Alphanumerics */
    AF_UNIRANGE_REC(0x2C60UL, 0x2C7FUL),      /* Latin Extended-C */
    AF_UNIRANGE_REC(0x2DE0UL, 0x2DFFUL),      /* Cyrillic Extended-A */
    AF_UNIRANGE_REC(0xA640UL, 0xA69FUL),      /* Cyrillic Extended-B */
    AF_UNIRANGE_REC(0xA720UL, 0xA7FFUL),      /* Latin Extended-D */
    AF_UNIRANGE_REC(0xFB00UL, 0xFB06UL),      /* Alphab. Present. Forms (Latin Ligs) */
    AF_UNIRANGE_REC(0x1D400UL, 0x1D7FFUL),    /* Mathematical Alphanumeric Symbols */
    AF_UNIRANGE_REC(0UL, 0UL)
};


AF_DEFINE_SCRIPT_CLASS(af_latin_script_class,
                       AF_SCRIPT_LATIN,
                       af_latin_uniranges,

                       sizeof(AF_LatinMetricsRec),

                       (AF_Script_InitMetricsFunc)af_latin_metrics_init,
                       (AF_Script_ScaleMetricsFunc)af_latin_metrics_scale,
                       (AF_Script_DoneMetricsFunc)NULL,

                       (AF_Script_InitHintsFunc)af_latin_hints_init,
                       (AF_Script_ApplyHintsFunc)af_latin_hints_apply
                       )


/* END */